44. (a) N2O3 (b) SF4 (c) AlCl3 (d) Li2CO3
46. H Br
δ+ δ−
48. The metallic potassium atoms lose one electron and form +1 cations,
and the nonmetallic fluorine atoms gain one electron and form –1 anions.
K → K+
+ e–
19p/19e–
19p/18e–
F + e–
→ F–
9p/9e–
9p/10e–
The ionic bonds are the attractions between K+
cations and F–
anions.
50. See Figure 3.6.
52. (a) covalent…nonmetal-nonmetal (b) ionic…metal-nonmetal
54. (a) all nonmetallic atoms - molecular (b) metal-nonmetal - ionic
56. (a) 7 (b) 4
58. Each of the following answers is based on the assumption that nonmetallic
atoms tend to form covalent bonds in order to get an octet (8) of
electrons around each atom, like the very stable noble gases (other than
helium). Covalent bonds (represented by lines in Lewis structures) and lone
pairs each contribute two electrons to the octet.
(a) oxygen, O
If oxygen atoms form two covalent bonds, they will have an octet of electrons
around them. Water is an example:
H O H
(b) fluorine, F
If fluorine atoms form one covalent bond, they will have an octet of electrons
around them. Hydrogen fluoride, HF, is an example:
H F
(c) carbon, C
If carbon atoms form four covalent bonds, they will have an octet of electrons
around them. Methane, CH4, is an example:
H H
H
H
C
(d) phosphorus, P
If phosphorus atoms form three covalent bonds, they will have an octet
Answer:
Explanation:
Hello.
In this case, since the chemical reaction is:
We next compute the moles of sodium carbonate from the 2.00 grams of calcium carbonate via their 1:1 mole ratio in the chemical reaction:
Thus, by knowing the molarity, we compute the volume:
Best regards.
Answer:
A FUSE is a type of conductor which protects the circuit by shorting it down when there is excess flow of current passing through it.
Explanation:
A fuse wire is made up of conducting materials such as alloy of tin and lead that has high resistivity. It has a low melting point of 200°C. It works based on the principle of heating effect of electric current. The functions of fuses include the following:
--> Fuses are made up of thin wire CONDUCTORS which interrupts or breaks the current flow of a circuit when in excess, thereby protecting the circuit from damage.
--> it prevents overload of current. In the event where too many appliances are connected to a single circuit, this can lead to overload which triggers a fuse to terminate the circuit connection.
--> It prevents total black-out: SWITCH-LIKE devices known as CIRCUIT BREAKERS share this function with the fuses. The nearest circuit breaks if any dysfunction occurs in the components of the circuit thereby preventing blackout.
Answer:
Option A. H₂O
Explanation:
PCl3 + 3H2O → H3PO3 + 3HCI
From the equation,
We can see clearly that for every 3moles of H2O, 1mole of PbCl3 is needed. This clearly indicates that H2O is the limiting reactant. This can further be proved by doing the following:
From the equation,
1mole of PbCl3 required 3moles of H20.
Therefore, 7moles of PbCl3 will require = 7x3 = 21moles of H2O. This amount(i.e 21moles) of H20 is far greater than what was given (i.e 5moles of H2O) from the question.
Now let us consider the reverse case as follows:
From the equation,
1mole of PbCl3 required 3moles of H20.
Therefore, Xmol of PbCl3 will require 5moles of H2O i.e
Xmol of PbCl3 = 5/3 = 1.67moles
This amount(i.e 1.67moles of PbCl3) obtained is smaller than what was given (i.e 7moles of PbCl3) from the question.
This shows that PbCl3 is excess and H20 is the limiting reactant
You are correct, the atomic number is always equal to the number of protons in the element. It is the relative atomic mass that is equal to the number of protons+neutrons. Electrons have no mass
